Multiple-spindle automatic lathes



Feb 6, 1962 c. A. BlscHol-F 3,019,510

MULTIPLE-SPINDLE AUTOMATIC v'Lxrmss Filed May 24, 1960 j ff E )00F d inlIIIHIIIIIIIIIIlilIIIIIIIIIIIIIIIIIIIII //7 Ven for @m4/es @/er/ fJ/fc/70// cete des Etablissements Malicet & Blin, Aubervilliers, France Filed May 24, 1960, Ser. No. 31,449 Claims priority, application France `luly 21, 1959 3 Claims. (Cl. 29-65) Multiple-spindle automatic lathes are provided with a number of transversely movable tool-carriers arranged on either side or both sides of a frame. Said frame carries in its center a cylindrical revolving spindle carrier, hereinafter called revolving head wherein are journalled the workpiece-carrying spindles (usually 4, 6 or 8 spindles) the axes of which are spaced on a circle having its center in the axis of the revolving head.

The revolving head is rotated stepwise about its axis each time through an angle equal to the angular distance between two successive spindles so that each spindle is presented in front of each tool-carrier.

Such a multiple-spindle automatic lathe will be called hereafter an automatic lathe of the type specied.

The arrangement to perform on each spindle successively the same operations to finally obtain identical pieces requires that each tool will stop in front of each successive spindle at exactly the same distance from the axis thereof.

In practice, whatever care has been exercised in the construction of such a machine, differences are observed from one spindle to another, due in particular to inaccuracy in the indexed angles of rotation of the revolving head. Consequently, the end of the feed motion of each tool-carrier must not be set with respect to the axis of the revolving head but with respect to the axis of each successive spindle in order to obtain identical pieces on all spindles.

In one of the known devices contrived for such a purpose, the end feed position is determined by the abutment of the tool-carrier on a peripheral ring provided on the revolving head. This results in applying substantial loads to the revolving head itself, which, after some time of use of the machine, may cause offsetting of the revolving head, which will impair the precision of the machine.

In order to avoid such an inconvenience, it has been proposed, in another known device, to provide the abutment, on the frame carrying said head rather than on the revolving head. In such a device, each tool-carrier has mounted thereon a number of adjustable stops, one for each spindle, and these stops are adapted successively to engage an intermediate part bearing on the frame and moving stepwise with the revolving head. Each stop of the tool-carriers is then adjusted according to the position taken by the axis of the corresponding spindle when cooperating with the relevant tool-carrier. However, such a device suffers from the drawback that, when the end position of the tool-carriers has to be changed (for reducing or increasing the diameter of the workpiece), every stop has to be newly adjusted.

lt is the primary object of the present invention to avoid the inconvenience of having to adjust individually all the stops corresponding to each spindle when it is desired to change the end position of the tool-carriers, while however maintaining the advantage that the abutment is eifective against the frame and not against the revolving head.

For this purpose, according to the present invention, an automatic lathe of the type specified comprises, for each tool-carrier, a rotating member carrying circumferentially spaced axially adjustable stops, and mounted for rotation about an axis parallel to the direction of movement of the tool-carrier, the number of said stops being equal to States Patent the number of spindles on the revolving head. Each stopcarrying member is stepwise rotated synchronously with the revolving head so as to bring each stop in turn in axial alignment with a single cooperating adjustable stop mounted on the corresponding tool-carrier, and said stop carrying member bearing transversely on the machine frame in the direction of the feed motion of the tool carrier.

Thus, for each tool-carrier the series of stops on the corresponding stop-carrying rotating member is adjusted once and for all according to the position of the axis of each spindle with respect to said tool-carrier. When it is necessary to adjust the diameter of the workpiece after a change of a tool, only the adjustable stop on the toolcarrier has to be readjusted.

In order that the invention may be clearly understood and readily carried into practice, an embodiment thereof will now be described more Ifully with reference to the accompanying drawings, in which:

FIG. l is a front view showing the arrangement of the spindles and tool-carriers in -a six-spindle automatic lathe according to the invention;

FIG. 2 is a corresponding side view showing the revolving head carrying frame and the rotating stop-carrying members with their actuating mechanism; and

FIG. 3 is a partially sectioned fragmentary plan View corresponding to FIG. 2, viewing along e axis of one of the rotating stop-carrier.

In the illustrated device, a pinion 1 meshes with the gear wheel v2 fixedly connected to the revolving spindlecarrying head 3.

The pinion 1 is mounted on a shaft 4 which carries at its other end a bevel gear pinion 5 meshing with another pinion 6 mounted on a transverse shaft 7 at each end of which is also mounted a bevel gear pinion 8 meshing with a pinion 9 to drive a vertical shaft 10 journalled in the frame at the corresponding side thereof.

Each vertical shaft 10 cariies three suitably spaced worms 11 each meshing with a worm gear 1.2 which is in fixed relation with a small stop-carrying member 13 rotatingly mounted in the frame and axially engaging said frame in the inward direction.

Each rotating member 13 carries six adjustable, circumferentially equally spaced stop-screws 14. Each adjustable screw 14 corresponds to one of the spindles.

On eac-h tool-carrier 15 is mounted an adjustable stopscrew 16 so positioned as to be axially aligned with each stop-screw 14 when the latter is in its working position.

If the revolving head 3 is rotated through 60 (angular space between two successive spindles), the gear 2 rotates the pinion 1 which, through the shaft 4, the bevel gears S, 6, the shaft 7 and the bevel gears 8, 9, drives the shaft 10 carrying the worms 11 which in turn actuate the worm gears 12 of the stop-carrying members 13. By suit ably choosing the gear ratios, it is arranged that the stopcarrying members rotate through the same angle as the revolving head 3, so that each stop-screw 14 corresponding to a respective spindle in each stop-carrying member 13 will come in turn in register with the stop-screw 16 of the corresponding tool-carrier 15 when said respective spindle will itself come in alignment with said correspond ing tool-carrier.

Of course, without depar-ting from the scope of the present invention as delined in the appended claims, modiiications may be made in the above described embodiment. Thus, the connecting drive between the revolving head 3 and the stop-carrying members 13 may be of any other suitable known type.

What I claim is:

l. In a multiple-spindle automatic lathe having a frame, a revolving head rotatably mounted in said frame and wherein are rotatably mounted, about axes parallel to the axis of rotation of said revolving head and spaced on a circle, a plurality of workpiece-carrying spindles, a plurality of tool-carriers in equal number to said spindles and mounted on said frame for transverse movement in a direction at right angles with the axis of said revolving head, the latter being adapted to be rotated stepwise so that each spindle in turn comes successively in Working relationship with each tool-carrier, in combination, a rotating member, for each tool carrier, carrying circumferentially spaced, axially adjustable stops, and mounted for rotation about an axis parallel to the direction of movement of the tool-carrier, the number of said stops being equal to the number of spindles on the revolving head, means for rotating said stop-carrying member stepwise and synchronously with the revolving head so as to bring each stop in turn in axial alignment with a single cooperating adjustable stop mounted on the corresponding tool- 4 carrier, said stop-carrying member bearing transversely on the machine frame in the direction of the feed motion of the tool-carrier.

2. A multiple-spindle automatic lathe according to claim 1, wherein said means for rotating said stop-carrying members consists of a mechanical gear device.

y 3. A multiple-,spindle automatic lathe according to claim 1, wherein said adjustable stops consist of adjustable screws.

References Cited in the le of this patent UNITED STATES PATENTS 

